Cut potatoes into quarters (or halves if small), place in a medium saucepan and cover with water. Boil until fork tender, about 10 minutes. Drain and put in a large bowl.
While potatoes are cooking, put olive oil, vinegar, lemon juice, mustard, garlic and salt and pepper in a small jar.
Shake dressing until blended and pour over warm potatoes. Add chopped fresh herbs and stir, breaking up potatoes to bite sized pieces. Adjust seasonings as needed.
Serve at room temperature. Or chill in the fridge and serve cold.